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| 2026-04-03 21:56:07 +0000 | merijn | (~merijn@host-cl.cgnat-g.v4.dfn.nl) (Ping timeout: 264 seconds) |
| 2026-04-03 21:48:49 +0000 | merijn | (~merijn@host-cl.cgnat-g.v4.dfn.nl) merijn |
| 2026-04-03 21:47:55 +0000 | <tomsmeding> | same for clang 21.1.6 |
| 2026-04-03 21:47:07 +0000 | <tomsmeding> | monochrom: I do not share your observations, I get no -Wunused-result for read(2) whatsoever on my system (linux, gcc 15.2.1), but I do get that warning for realloc() regardless of the optimisation level |
| 2026-04-03 21:47:05 +0000 | <monochrom> | When confronted with an unused-value problem, some people go, "I know, I will store it in a fresh variable!". Now they have two problems. >:) |
| 2026-04-03 21:44:41 +0000 | <tomsmeding> | monochrom: although now you have a -Wunused-but-set-variable ;) |
| 2026-04-03 21:44:00 +0000 | <tomsmeding> | yes, I'm a little confused too |
| 2026-04-03 21:43:41 +0000 | <monochrom> | Adding "int r; r =" kills the warning under -O2. So it is not even like "we need an elaborate live-variable analysis to discover unused results" :) |
| 2026-04-03 21:37:56 +0000 | synchromesh | (~john@2406:5a00:2412:2c00:343e:4e23:bce:73a3) synchromesh |
| 2026-04-03 21:36:55 +0000 | merijn | (~merijn@host-cl.cgnat-g.v4.dfn.nl) (Ping timeout: 264 seconds) |
| 2026-04-03 21:36:19 +0000 | <tomsmeding> | I guess https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wunused-result is the better link |
| 2026-04-03 21:35:53 +0000 | synchromesh | (~john@2406:5a00:2412:2c00:343e:4e23:bce:73a3) (Read error: Connection reset by peer) |
| 2026-04-03 21:35:52 +0000 | <tomsmeding> | the manual doesn't elucidate: https://gcc.gnu.org/onlinedocs/gcc/Common-Attributes.html#index-warn_005funused_005fresult |
| 2026-04-03 21:35:14 +0000 | <monochrom> | So I still don't know why! :) |
| 2026-04-03 21:34:41 +0000 | <monochrom> | No warning until -O2 |
| 2026-04-03 21:34:32 +0000 | <monochrom> | OK I have: int main(void) {char b[100]; read(0, b, 100); ... |
| 2026-04-03 21:33:22 +0000 | <tomsmeding> | not saying there are none, I just can't think of any :) |
| 2026-04-03 21:32:44 +0000 | <tomsmeding> | that... has nothing to do with optimisations? fork() doesn't care whether you used -O2 if it wants to fail |
| 2026-04-03 21:32:11 +0000 | <monochrom> | I forgot. I seem to recall that unused-return-value is one of them. |
| 2026-04-03 21:31:42 +0000 | merijn | (~merijn@host-cl.cgnat-g.v4.dfn.nl) merijn |
| 2026-04-03 21:31:37 +0000 | <tomsmeding> | warning about = vs == is independent of optimisations |
| 2026-04-03 21:31:21 +0000 | <tomsmeding> | what kind of warnings would become more important under optimisations? |
| 2026-04-03 21:31:00 +0000 | <monochrom> | At least there is a strong correlation between unoptimized and bad code working fine. |
| 2026-04-03 21:30:54 +0000 | <tomsmeding> | ideologically it's a little more nuanced |
| 2026-04-03 21:30:36 +0000 | <tomsmeding> | observationally, yes |
| 2026-04-03 21:30:27 +0000 | <monochrom> | Ah OK. I think the two are logically equivalent. :) |
| 2026-04-03 21:30:20 +0000 | <tomsmeding> | but this is from memory -- not 100% sure |
| 2026-04-03 21:30:04 +0000 | <tomsmeding> | or, reformulated, they think it's not worth generating the warnings if that's the only reason for running the analysis |
| 2026-04-03 21:29:57 +0000 | <monochrom> | I was guessing that it was because -O2 breaks more code under beginner mistakes. |
| 2026-04-03 21:29:44 +0000 | <tomsmeding> | IIRC some of the analyses needed to produce the warnings are only computed for the benefit of particular optimisations |
| 2026-04-03 21:29:21 +0000 | <monochrom> | I don't know. Is that it? |
| 2026-04-03 21:29:07 +0000 | <tomsmeding> | isn't that to make ghc -O0 faster? |
| 2026-04-03 21:28:44 +0000 | <monochrom> | gcc -O2 turns on more warnings than -O0. Anyone want to bring that ideology to GHC? Maybe next April 1? >:) |
| 2026-04-03 21:25:03 +0000 | <monochrom> | OK I like -W now. Didn't know that it exists. |
| 2026-04-03 21:24:00 +0000 | Square3 | (~Square@user/square) Square |
| 2026-04-03 21:21:43 +0000 | absurdvoid | (~absurdvoi@user/absurdvoid) absurdvoid |
| 2026-04-03 21:20:42 +0000 | merijn | (~merijn@host-cl.cgnat-g.v4.dfn.nl) (Ping timeout: 255 seconds) |
| 2026-04-03 21:20:23 +0000 | Guest20 | (~Guest20@149.3.7.235) |
| 2026-04-03 21:19:55 +0000 | absurdvoid | (~absurdvoi@user/absurdvoid) (Ping timeout: 268 seconds) |
| 2026-04-03 21:16:56 +0000 | <tomsmeding> | (I just wrote one) |
| 2026-04-03 21:16:55 +0000 | <monochrom> | But most importantly, the OOP world did not freak out and added -Wunused-return-value to their -Wall. |
| 2026-04-03 21:16:28 +0000 | <tomsmeding> | ah, and 8% of the remaining cases are forkIO |
| 2026-04-03 21:16:13 +0000 | <monochrom> | `char` returning the character you already know is a nicety that you have the full right to use or ignore. SImilarly to in the OOP world most methods return this so you can chain o.m1().m2().m3(). (Especially popular among the JS people.) |
| 2026-04-03 21:15:50 +0000 | <tomsmeding> | well that explains :p |
| 2026-04-03 21:15:43 +0000 | <tomsmeding> | nice |
| 2026-04-03 21:15:39 +0000 | merijn | (~merijn@host-cl.cgnat-g.v4.dfn.nl) merijn |
| 2026-04-03 21:15:35 +0000 | <geekosaur> | along with a lot of example code which assumed `-Wunused-do-bind` didn't exist |
| 2026-04-03 21:15:03 +0000 | <tomsmeding> | adding a _ to a mapM is really not the problem |
| 2026-04-03 21:14:44 +0000 | <geekosaur> | parsec by a decade, I think |
| 2026-04-03 21:14:41 +0000 | <tomsmeding> | because in my (mostly pointless) following of -Wunused-do-bind in my code, 90% of the annoying cases where I add a pointless `_ <-` are for `char` |